A Relativistic Description of Gentry's New Redshift Interpretation

We obtain a new expression of the Friedmann-Robertson-Walker metric, which is an analogue of a static chart of the de Sitter space-time. The reduced metric contains two functions, $M(T,R)$ and $\Psi(T,R)$, which are interpreted as, respectively, the mass function and the gravitational potential. We find that, near the coordinate origin, the reduced metric can be approximated in a static form and that the approximated metric function, $\Psi(R)$, satisfies the Poisson equation. Moreover, when the model parameters of the Friedmann-Robertson-Walker metric are suitably chosen, the approximated metric coincides with exact solutions of the Einstein equation with the perfect fluid matter. We then solve the radial geodesics on the approximated space-time to obtain the distance-redshift relation of geodesic sources observed by the comoving observer at the origin. We find that the redshift is expressed in terms of a peculiar velocity of the source and the metric function, $\Psi(R)$, evaluated at the source position, and one may think that this is a new interpretation of {\it Gentry's new redshift interpretation}.Comment: 11 pages. Submitted to Modern Physics Letters

Magnetic Flux Loss and Flux Transport in a Decaying Active Region

We estimate the temporal change of magnetic flux perpendicular to the solar surface in a decaying active region by using a time series of the spatial distribution of vector magnetic fields in the photosphere. The vector magnetic fields are derived from full spectropolarimetric measurements with the Solar Optical Telescope aboard Hinode. We compare a magnetic flux loss rate to a flux transport rate in a decaying sunspot and its surrounding moat region. The amount of magnetic flux that decreases in the sunspot and moat region is very similar to magnetic flux transported to the outer boundary of the moat region. The flux loss rates [$(dF/dt)_{loss}$] of magnetic elements with positive and negative polarities are balanced each other around the outer boundary of the moat region. These results suggest that most of the magnetic flux in the sunspot is transported to the outer boundary of the moat region as moving magnetic features, and then removed from the photosphere by flux cancellation around the outer boundary of the moat region.Comment: 16 pages, 7 figures, Accepted for publication in Ap

Atomic matter wave scanner

We report on the experimental realization of an atom optical device, that allows scanning of an atomic beam. We used a time-modulated evanescent wave field above a glass surface to diffract a continuous beam of metastable Neon atoms at grazing incidence. The diffraction angles and efficiencies were controlled by the frequency and form of modulation, respectively. With an optimized shape, obtained from a numerical simulation, we were able to transfer more than 50% of the atoms into the first order beam, which we were able to move over a range of 8 mrad.Comment: 4 pages, 4 figure

Nucleotide specificity of the enzymatic and motile activities of dynein, kinesin, and heavy meromyosin.

The substrate specificities of dynein, kinesin, and myosin substrate turnover activity and cytoskeletal filament-driven translocation were examined using 15 ATP analogues. The dyneins were more selective in their substrate utilization than bovine brain kinesin or muscle heavy meromyosin, and even different types of dyneins, such as 14S and 22S dynein from Tetrahymena cilia and the beta-heavy chain-containing particle from the outer-arm dynein of sea urchin flagella, could be distinguished by their substrate specificities. Although bovine brain kinesin and muscle heavy meromyosin both exhibited broad substrate specificities, kinesin-induced microtubule translocation varied over a 50-fold range in speed among the various substrates, whereas heavy meromyosin-induced actin translocation varied only by fourfold. With both kinesin and heavy meromyosin, the relative velocities of filament translocation did not correlate well with the relative filament-activated substrate turnover rates. Furthermore, some ATP analogues that did not support the filament translocation exhibited filament-activated substrate turnover rates. Filament-activated substrate turnover and power production, therefore, appear to become uncoupled with certain substrates. In conclusion, the substrate specificities and coupling to motility are distinct for different types of molecular motor proteins. Such nucleotide "fingerprints" of enzymatic activities of motor proteins may prove useful as a tool for identifying what type of motor is involved in powering a motility-related event that can be reconstituted in vitro

An AC electric trap for ground-state molecules

We here report on the realization of an electrodynamic trap, capable of trapping neutral atoms and molecules in both low-field and high-field seeking states. Confinement in three dimensions is achieved by switching between two electric field configurations that have a saddle-point at the center of the trap, i.e., by alternating a focusing and a defocusing force in each direction. AC trapping of 15ND3 molecules is experimentally demonstrated, and the stability of the trap is studied as a function of the switching frequency. A 1 mK sample of 15ND3 molecules in the high-field seeking component of the |J,K>=|1,1> level, the ground-state of para-ammonia, is trapped in a volume of about 1 mm^3

Shape coexistence in Lead isotopes in the interacting boson model with Gogny energy density functional

We investigate the emergence and evolution of shape coexistence in the neutron-deficient Lead isotopes within the interacting boson model (IBM) plus configuration mixing with microscopic input based on the Gogny energy density functional (EDF). The microscopic potential energy surface obtained from the constrained self-consistent Hartree-Fock-Bogoliubov method employing the Gogny-D1M EDF is mapped onto the coherent-state expectation value of the configuration-mixing IBM Hamiltonian. In this way, the parameters of the IBM Hamiltonian are fixed for each of the three relevant configurations (spherical, prolate and oblate) associated to the mean field minima. Subsequent diagonalization of the Hamiltonian provides the excitation energy of the low-lying states and transition strengths among them. The model predictions for the $0^{+}$ level energies and evolving shape coexistence in the considered Lead chain are consistent both with experiment and with the indications of the Gogny-EDF energy surfaces.Comment: 12 pages, 6 figures, 1 tabl

Electrodynamic trapping of spinless neutral atoms with an atom chip

Three dimensional electrodynamic trapping of neutral atoms has been demonstrated. By applying time-varying inhomogeneous electric fields with micron-sized electrodes, nearly $10^2$ strontium atoms in the $^1S_0$ state have been trapped with a lifetime of 80 ms. In order to design the electrodes, we numerically analyzed the electric field and simulated atomic trajectories in the trap, which showed reasonable agreement with the experiment.Comment: 4pages, 4figures, to appear in Phys. Rev. Let

Testing Spatial Noncommutativity via Rydberg Atoms

The possibility of testing spatial noncommutativity via Rydberg atoms is explored. An atomic dipole of a cold Rydberg atom is arranged in appropriate electric and magnetic field, so that the motion of the dipole is constrained to be planar and rotationally symmetric. Spatial noncommutativity leads to that the canonical angular momentum possesses fractional values. In the limit of vanishing kinetic energy, the dominate value of the lowest canonical angular momentum takes $\hbar/2$. Furthermore, in the limit of eliminating magnetic field, the dominate value of the lowest canonical angular momentum changes from $\hbar/2$ to $\hbar/4$. This result is a clear signal of spatial noncommutativity. An experimental verification of this prediction is suggested.Comment: 10 pages. Physical Review Letters (in press

Giant Quantum Reflection of Neon Atoms from a Ridged Silicon Surface

The specular reflectivity of slow, metastable neon atoms from a silicon surface was found to increase markedly when the flat surface was replaced by a grating structure with parallel narrow ridges. For a surface with ridges that have a sufficiently narrow top, the reflectivity was found to increase more than two orders of magnitude at the incident angle of 10 mRad from the surface. The slope of the reflectivity vs the incident angle near zero was found to be nearly an order of magnitude smaller than that of a flat surface. A grating with 6.5% efficiency for the first-order diffraction was fabricated by using the ridged surface structure.Comment: 5 pages, 4 figures. To be published in J. Phys. Soc. Jp